var ctrlMan = m_Map.GetCtrlMan();
var ctrlstate = ctrlMan.GetControlState();
var layerMan = ctrlMan.GetLayerMan();

var layer = layerMan.FindLayer(1);
if (layer)
    layer.DestroyLayer();

    CXCtrlMan ctrlman = m_Map.GetCtrlMan();
    CXLayerMan layerman = ctrlman.GetLayerMan();
    CXBaseMan baseman = layerman.CastToBaseManager();
    CXUtility util = m_Map.GetUtility();
    CXLayer obj  = layerman.FindLayer(100);
    if(obj!=NULL) {
        obj.DestroyLayer();
     }